Mechanical flexibility, strain-tunable electronic structure, and photovoltaic potential of the Janus SbSeCl monolayer: A first-principles study

The multifunctional potential of the Janus SbSeCl monolayer is investigated using first-principles calculations of its structural, mechanical, electronic, transport, optical, and photovoltaic properties. Phonon-dispersion and elastic-constant analyses confirm its dynamical and mechanical stability, while a low Young's modulus of 30.93 Nm −1 indicates pronounced in-plane flexibility. The Janus SbSeCl monolayer is an indirect-bandgap semiconductor with a bandgap of 1.84 eV, which decreases to 1.33 eV under a biaxial strain of 0.08 while retaining its semiconducting character. Deformation-potential calculations predict electron mobilities of approximately 800 cm 2 V −1 s −1 . Combined with strong broadband absorption in the visible–ultraviolet range, reaching 10 6 cm −1 , this efficient carrier transport establishes SbSeCl as a promising photovoltaic donor. Accordingly, an SbSeCl/InSeCl donor–acceptor heterostructure is proposed, exhibiting a small lattice mismatch of 1.48%, a favorable conduction-band offset of 0.06 eV, and an estimated power conversion efficiency of 17.88%. These results highlight SbSeCl as a promising material for flexible electronics and ultrathin photovoltaic devices.